Carburetor



Nov. 1o, 1936.

H. L..v JOHNSON CARBURETOR Filed June ll, 1934 2 Sheets-Sheet 1 Nov. 10, 1936. H. 1 JoHNso-N CARBURETOR Filed June ll, 1934 2 Sheets-Sheet 2 Patented Nov. 10, 1936 PAT-'ENT OFFICE CARBURETOR I-Iarry L. Johnson, Waukegan, Ill., assignor to Johnson yBrothers Engineering Corporation, Waukegam Ill., a corporation of Indiana Application June 11, 1934, Serial No. 729,950

5 Claims.

This invention relates in general to a carburetor and has more particular reference to a delay feed carburetor having a jet nozzle for supplying fuel at lownor medium-'speeds-and an open throttle nozzle for providing a delay feed.

'In the 1 ordinary operation of a two-cycle or other gasoline engine, a quantity of fuel con- 4denses `an'd'collects in the pipes and passages vfrom'the ordinary carburetor to the combustion chamber of the engine solthat when the throttle is opened tolits fullest or'nearly fullextent, an immediate additional supply-of fuel is neither desirable nor necessary until the fuel which has collectedin= thepassages `from vthe carburetor to the combustion chamberhas been absorbed or carried away. The presentinvention therefore provides a delay interval'forfthe additional open throttle fuel feed-which issuflicient to take care of the condensation and accumulation ofl fuel before the additional'feed is effective.

'It is therefore an important object of the presentlinvention` tofprovidea carburetor'vvlth afuel .jet nozzle fforfordinaryand slow `speed running and anadditional-fuel jet nozzle witha :supply pipe having-'a certain capacity-and providing a delay feed for thev additional jet nozzle whichsis operative only at high speed or with an approximately full open throttle.

VvA further object ofthe invention is in the'provision of -a fuel Vfeeding device which provides a 'rapid acceleration ofl an-enginefrom low throttle speedsfto mediurnand 'full open throttlespeeds and to cause a. smooth feeding and supply of fuel to an engine by the construction herein shown and described.

Other objects of 4thefinventionvwill appear hereinafter, `the preferred construction being illustrated in the accompanying drawings, in which `Fig. lis aside elevation of a delayfeed car- "buretor in accordance with theprinciples of this invention;

vFig. 2 isa'section takenon the line 2-2 of Fig. -1;

Fig. 3 is a sectio-n taken on the line 3 3 of Fig. 1; and

' Fig.` is `a-'part` sectional 4.View taken onthe line When anengine'isfrunning normally at low or medium speed,-an`d particularly an engine of the ltwo-cycle -type lin which oil -is frequently mixed with'the gasoline for lubricating the engine, it is Vfound that the lubricant as Well as the fuel tends 'to-*condense `upon the walls of the fuel passage lfrom the carburetor to the enginethe amount of -suchfcondensationor collection depending more L23 inserted through the wallof the body 6.

is. supplied immediately yunder such conditions there will'be an excessv of fuel and the smooth acceleration of the engine will be retarded rather than assisted. VThe present invention provides for a retarded supply offadditionalffuel due to the'capacity of the pipeitself and the time interval necessary to fill the pipe and discharge fuel from the high speed jet nozzle.

vReferring now more particularly to the draw,- ings, a carburetor block or body 6 has an air inlet vf'l, a throttle chamber 8 and a fuel passage 9 formed therein. At one side of the block is an extension forming a fuelchamber Il) having a threaded tubular portion II at the bottom connected by means of a pipe `I2 with a suitable source of fuel supply. In the tubular portion II is a perforated valve plug I3 through which extends a valve stem I4 carrying a Valve I5 to close the valve opening I6. Mounted on the stem I4 in the chamber I0 is a oat I'l carrying a float adjustment plate I8 secured to the float by a screw I9. The upper end of the stem extends through a centering opening in a cap v20 which closes the top of the chamber I0, the cap being held yieldingly in place by a spring 2l extending 'laterally from the side of the chamber.

In the throttle chamber 8 which is preferably circular in-transverse section is a bottom filler plate 22 (Figs. 2 and 3) held in place by a screw The inner face of this plate forms a chord at the bottom of the chamber 8 and extending upwardly through a passage 24 in the bottom 6 is a lower jet nozzle 25 having an opening or openings 26 at its upper end closely adjacent the lower edge of the throttle chamber and the lower side of the plate 22. Rotatable in the chamber 8 is a throttle 2'! which arches the chamber 8 from the l opposite central portions thereof as shown in Fig. 3, but is segmental in cross section as shown in Fig. 2, to substantially close the passage when rotated to the broken line position as shown in Fig. 2. An operating stem 28 extends from onev end of the throttle 21 through a support 29 secured to and projecting vfrom the valve body 6 which forms a support therefor. Attached to the outer end of the throttle stem 28 by means ofa pin 30 is an operating arm `3I having a suitable connection for rotating the stem and the throttle 21 as desired. Between the arm 30 and the projection 29 and surrounding the stem is a coil spring 32 with their bearing washers 33 holding the throttle 21 yieldingly in any position in which it is set.

The outer end of the fuel passage 24 is closed in the block E by a plug screw 34 and extending transversely to the passage is another fuel passage 35 leading by means of a reduced portion 35 into the fuel chamber I0. In this passageway 34 an adjusting valve 31 is threaded having a pointed end 38 to adjustably close the reduced portion 36 and a head 39 extending without the body by means of which the valve is adjusted for admitting more or less fuel from the chamber IU to the throttle chamber 8.

Communicating with one side of the fuel chamber I8 through a passage 4D at the bottom of the chamber is a vertical passage 4| in which a needle valve 42 is threaded having a pointed lower extremity 43 and an upper adjusting head 44. Extending laterally from the passage 4l above the pointed extremity of the needle valve 42 is a passage 45 formed in part by an angle fitting 46. Connected to the outer end of this fitting is a delay pipe 41, the other end of which is connected by an angle tting 48 with the top of the fuel passage 1 but with a jet nozzle 50 extending into the passage from the top thereof and having jet openings 5l at the inner end.

Also mounted and rotatable in the fuel passage 1 is a choke valve 52 having an opening 53 in its lower edge and mounted for rotation upon a stem 54 which extends through opposite sides of the body member with a bearing nut 55 at one end and an operating arm 56 at the other end secured to a bearing sleeve 51 which is yieldingly held in place by a spring 58 and a nut 59 at the adjacent end of the stem 54.

The high speed nozzle 59 is positioned between the throttle valve chamber 8 and the choke valve 52 and in a partially closed position of the throttle 21 the high speed nozzle 5U will not be subject to sufcient suction to draw fuel therefrom. When the throttle is open to the fullest extent as shown in Fig. 2, and with the choke open the high speed nozzle 50 will be subject to considerable pressure, causing suction therein and an additional flow of fuel from this nozzle. The globules or particles of oil or fuel 60 as represented in Fig. 2, indicate the presence in the fuel passage of condensation or accumulation which is rst taken up by the passage of high speed air through the carburetor when the throttle is opened.

Assuming that the gasoline engine to which the carburetor is applied is running at low or medium speed under partially open throttle, the low speed jet nozzle 25 only is in operation and supplying fuel. The full speed nozzle 50 is dormant; any fuel from this nozzle has returned to the fuel chamber IU due to gravity. As the throttle 21 is opened for higher engine speeds the inco-ming fuel drawn by the increased suction from the engine acts upon the high speed nozzle 50 causing it to draw additional fuel from the float chamber I0 through the delay pipe 41. Due to the length or capacity of this delay pipe 41 a predetermined interval of time is necessary to ll the pipe before the fuel will be discharged from the high speed nozzle 5D, thereby allowing time for the engine to receive most of the fuel which has accumulated throughout the Various passages of the carburetor and the engine, This will prevent too rich a fuel mixture from being supplied to the engine as soon as the throttle is opened wide and will cause a more normal and a more rapid acceleration of the engine from low throttle speeds to medium and full open throttle speeds. A continuation of the full open throttle will cause additional fuel to be drawn from the high speed jet nozzle thereby supplying sucient fuel from the low and high speed jet nozzles for high speed operation of the engine.

It will be noted that the air inlet to the oarburetor is first downwardly toward the low speed jet nozzle 25 and then inclines upwardly in the fuel passage 9, the throttle 21 causing in effect a restricted area at its low speed or partially closed position, the engine suction drawing the air directly over the nozzle 25 and its openings 26 to produce the desired suction.

When the throttle is closed or partially closed after being full open the engine suction is reduced on the upper jet nozzle and the fuel in the delay pipe 41 falls or returns by gravity to the fuel chamber I0.

Both of the jet nozzles are controlled by needle adjustments so that the amount of fuel can be varied as desired, and the throttle and choke Valves are controlled in any well known manner by the movement of their operating members. Bo-th the high and low speed jet nozzles receive fuel from the same fuel chamber and a single float is sucient to maintain a proper level of fuel in the fuel chamber.

I claim:

l. A carburetor comprising a transverse air and fuel passage which rst extends downwardly and then inclines upwardly through the carburetor body, a fuel feeding nozzle in the lowest part of the passage, a throttle valve for controlling the flow of air through the passage, a high speed fuel nozzle extending downwardly from the top of the passage at the rear side of the throttle, a common fuel chamber for the nozzles, and a delay pipe extending upwardly from the fuel chamber to the upper nozzle and having a predetermined capacity whereby the upper fuel nozzle delivers fuel to the passage only when the throttle is open a predetermined amount.

2. A carburetor having a transverse air and fuel passage, a throttle Valve therein, a choke valve in the passage at a distance behind the throttle valve, a fuel feeding nozzle extending upwardly from the bottom of the passage adjacent the forward portion of the path of travel of the throttle valve, a second fuel nozzle exn tending downwardly from the top of the passage between the throttle and choke valves and in the path of air in the passage only when the throttle valve is opened to a predetermined cxtent, and a fuel feeding pipe for the second fuel nozzle which has a predetermined liquid capacity such that it is gradually lled with liquid depending upon the throttle opening which delays fuel feeding through the nozzle to that extent.

3. A delay feed carburetor comprising an air and fuel passage, a throttle valve therein, a fuel feeding nozzle in the bottom of the passage adjacent the forward portion of the throttle valve chamber, a high speed nozzle extending downwardly in the passage at the rear of the throttle, and a delay feed pipe extending from below the passage to the high speed nozzle and of a predetermined capacity such that the pipe must first be filled depending upon the setting of the throttle and the feeding of fuel therefrom is delaved to a predetermined extent after the throttle valve is opened to its fullest extent in the fuel passage.

4. A delay feed carburetor having a transverse air and fuel passage, a throttle valve chamber and a valve movable therein, a low speed fuel nozzle extending in the bottom of the passage adjacent the front of the throttle chamber, the air and fuel passage back of the throttle valve providing for the condensation and accumulation of sulplus fuel therein, a high speed fuel nozzle extending downwardly at the top of the passage and being operative only when the throttle valve is opened to a predetermined extent, a delay fuel feed pipe in connection with the high speed nozzle being effective only when the throttle valve is opened to a predetermined extent whereby the surplus fuel in the passage will first be taken up before the high speed nozzle is effective after the opening of the throttle.

5. A delay feed carburetor having an air and fuel passage, a throttle valve therein, a high speed fuel nozzle in the bottom of the passage adjacent the valve, for low speed engine operation, a high speed fuel nozzle extending downwardly from the top of the passage at the rear of the throttle valve, a common fuel chamber, a delay feed pipe extending from the chamber to the high speed fuel nozzle, the passage being adapted to receive the condensation and accumulation of the fuel therein during low speed operation of an engine to which the carburetor is attached, and the high speed nozzle being effective only when the throttle is opened to a predetermined extent, the delay feed pipe preventing the discharge of fuel from the high speed nozzle until a predetermined time after the opening of the throttle to take up the accumulation of fuel in the said passage before the high speed nozzle is effective.

HARRY L. JOHNSON. 

